Deke Slayton II Cygnus moved to SLC-41 in preparation for Dec. 3 launch
CAPE CANAVERAL, Fla. — Colorado-based United Launch Alliance (ULA) has moved an Atlas V 401 rocket carrying Orbital ATK’s Deke Slayton II Cygnus to Space Launch Complex 41 from the adjacent Vertical Integration Facility (VIF) located at Cape Canaveral Air Force Station. The launch vehicle and its precious cargo were moved out to the pad at 10:05 a.m. EST (15:05 GMT).
At present, the fourth operational flight of a Cygnus spacecraft to the International Space Station is set to lift off at 5:55 p.m. EST (22:55 GMT) on Thursday, Dec. 3.
Tomorrow’s planned flight will be unique for various reasons: the method of delivery to orbit and the amount of time to get the booster and its precious cargo off of the pad and into the early evening skies. It will break the norm in terms of typical cargo flights leaving for the ISS from the Cape.
Before Thursday’s planned launch, only SpaceX’s Falcon 9 rocket had conducted commercial resupply runs to the orbiting lab from the Cape. For those nine flights, the NewSpace firm only had 1 second to get their booster and the Dragon spacecraft off the launch pad. This is not the case with the OA-4 mission.
The ULA launch team has a 30-minute launch window – a substantial increase compared to the “instantaneous” launch windows that SpaceX has available to them.
Outside of the U.S., the international partners involved with ferrying supplies to the outpost also deal with instantaneous launch windows. The Russian Soyuz, Japanese H-IIB, and European Ariane 5 all have similar windows.
According to a report appearing on SpaceFlight Now, resupply missions’ launch windows are partly dictated so that spacecraft are able to rendezvous to the ISS. The fact that the OA-4 (as well as the planned March 2016 OA-6 mission) has a 30-minute launch window is due in large part to the capabilities of the Atlas V 401 that will be pushing the mission out of Earth’s gravity well.
Cygnus’ normal ride uphill is the Orbital ATK Antares booster. After the loss of the Orb-3 mission on Oct. 28, 2014, some 12 seconds into the flight, the firm needed to find a new rocket while Antares underwent redesign so as to be able to carry out the requirements they have under the $1.9 billion Commercial Resupply Services contract with NASA.
The loss of the original Deke Slayton Cygnus spacecraft was most likely caused by a fault in the turbopump of one of two AJ26 rocket engines in Antares’ first stage.
Dulles, Virginia-based Orbital ATK had to work quickly to find a launch vehicle to return Cygnus to service as soon as possible – that’s where United Launch Alliance came in.
“Literally days after the Orb-3 failure we were calling launch vehicle providers to find out what was available, what might fit and how we might work with all of them…,” Dan Tani, a former NASA shuttle astronaut and current Orbital ATK vice president of mission and cargo operations told SpaceFlight Insider. “We narrowed the field down to a couple and ULA was, of course, one of them.”
With the new Launch Service Provider in place, Orbital ATK was in a good place in terms of being able to continue their efforts under NASA’s CRS program.
“They, very fortunately, had a late 2015 slot, and that was the timeframe that we wanted, we actually wanted something a little earlier, but we’re very happy with this December launch slot,” Tani said.
Tomorrow’s Atlas V launch will be the final flight that United Launch Alliance will conduct under its 2015 manifest. It also is the first mission that ULA will participate in under NASA’s CRS contract, the 60th flight of an Atlas V booster and the 30th time that the 401 configuration of the rocket has been tapped to carry out a mission.
Current weather predictions provide a 60 percent chance of favorable conditions to support the launch. However, as is so often the case with the turbulent Florida weather, this is subject to change.
For their part, Orbital ATK noted the historic and logistical importance of the Cygnus spacecraft’s return to service.
“With the naming of this spacecraft, we continue our commitment to honor the late Donald ‘Deke’ K. Slayton, one of the original Mercury Seven astronauts and a champion of America’s commercial space program and leadership in space,” said Frank Culbertson, President of Orbital ATK’s Space Systems Group. “We are pleased that the enhanced Cygnus that bears his name will be able to provide up to 53 percent more in cargo weight to the International Space Station than our previously flown standard version.”
Video courtesy of NASA
Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.